Acoustic device provided with vibratile diaphragms



P 1, 1931- K. s. s. SPENCER 1,821,529

ACOUSTIC DEVICE PROVIDED WITH VIBRATILE DIAPHRAGMS Filed May 51, 1928 2Sheets-Sheet 1 A FIGJ.

INVENTOR.

P v1, 9 K. s. s. SPENCER ,821,529

ACOUSTIC DEVICE PROVIDED WITH VIBRATILE DIAPHRAGMS Filed lay 31. 1928 2Sheets-Sheet 2 mum KENNETH SEbasrrmu Smvwn, SPc-wcnt,

' ,I'nvenwn Patented Sept. 1, 1931' PATENT OF F ICE xmmsmaman Loous'ncnxv ca raovrnan wrrn maa'rxm nmmons I Lppllution fled la, 81, 1928,Serial at. 281,868, and in Great Britain June it, 192?.

This invention relates to loud speakers em ploying cone diaphragms ofthe direct act 111 type.

The distortion of various frequencies out the musical range and blastingare mainiy" attributed to the nature and arrangement of the diaphragmand although the perform ance of loud ,speakershas been very greatlyimproved within recent years, the best re sults are obtained only bycomparatively expensive means and devices which are often inconvenientlylarge for ordinary purposes! The object of the resent invention is toprovide a loudspea er with a diaphragm structure or arrangement which isconvenient to use and gives clear undistorted duction.

To attain this object use is made p rality of conical dia hragms of thedirect acting type and of ifierent dimensions shape, so mounted andactuated that undesired resonant efiects are obviated. A convenientarran ment is to have two conical diaphragms o difierent angularitieswhose apexes are co-axial, the space between bein unenclosed. If theperipheries diap ra s be in approximately the same plane, t e loudspeaker may be ve snugiy mounted within the cabinet and i desired thediaphra smay very easily be provided with a perip eral hinge member.

The invention is illustrated in the accom pa'nying drawings in which:

Fig. 1 isa front view of a loud speaker accordin to the invention,

Fig. 2 1s a sectional plan view of the loud speaker of Fig. 1,

Fig. 3 is a sectional side elevation showing schematically amodification in dim phragm structure.

Figs. 4 and 5 show in sectional side sieve tion further modificationsofthe diaphragm structure.

The sound producing element comprises a pluralit of cone diaphragms 1and 2, which are of ifierent angularity. The are sup ported upon a bolt6 by means 0 spac s and 5 which may conveniently be mad any lightmaterial. The bolt 6 is r secured to an armature 3 of the elect:

m an

s-which ma olimg the The eiect cal.

ent coup sion in spring r leads tothe dri J as shown 16 positioned upona panei 11, secured a e s i Ci the cabinet eripheries l thrown" 'nd 2 toen n.

s a y free to vibrate this case it is iound advisable to'turn back theed e the diaphragms for say half an inch from the periphery as shown inFig. 4e.

in order regiiiate the pressure which die, the "felt pads 2 1 o 81' HUGHcam st and support heitsld passing throw Bet the panel 11. t ngs aresituated. a nuts lo eositionin he diaphragms may readily eifecte "linefront panel of the cabinet is provided with openings 19 through whichsound waves may to emitted 'tlisi i of diaphr f The anel has alsoopenings 18 which aiiow souno wares, generated by diaphragm have readyaccess o the outside air. E-

" chamber been found th e are obviated, also the IBDZOdLLiLti"). offrequencies over an extremely broad reuse is obtained with greatfaithfulness.

The diaphragm a e preferabiy made f stiff aper in manner, and the fe redarrange tion clamped to the front wall of the cabinet, the peripheralportion being 'sufliciently flexible to allow the effectual vibration ofthe diaphragms to take place, but at the same 5 time serving to cut outor prevent the setting up of transverse vibrations or blasting. I

The term conical is meant to cover not only right circular cones butshapes which are analo ous in operation.

The scbematic representation of Fig. 3 shows a modification in whichinstead of two, three cone diaphragms are used. The prefered angle ofthe third cone is clearly shown.

In all the arrangements it is preferable that the peripheries of thecones should lie in the same plane, but of course this is not essentialsince the main advantage is merely one of construction.

As shown in Fig. 3 the diaphragms 21, 22

and 23 are supported on a bolt 24.- by means of s acers 25. The bolt 24would be secured to t e armature of the driving mechanism.

The loud speaker may be mounted in a cabinet by itself, or together withthe other desired wireless receiving apparatus.

What is claimed is:

1. In a loud speaker a driving element, a plurality of conicaldiaphragms of different angularities operatively connected to said 1driving element, and an opening between the peripheries of saiddiaphragms.

2. In a loud speaker a driving element, a cone diaphragm operativelyconnected to said driving element, a second cone diaphragm of differentangularity to said first diaphragm also operatively connected to saiddriving element and with its periphery in substantially the same planeas the periphery of the first said diaphragm and spaced a slightdistance therefrom.

3. In a loud speaker a driving element, a plurality of conicaldiaphragms of different angularlties operatively connected to said driviof sai cabinet in proximity to the peripheries of said diaphragm, aspace in said wall registering with the o ening between said dia hragms,and anot or opening in said 4. In a loud speaker a driving element, aplurality of cone diaphragms of difi'erent angularlties operativelyconnected to said driving element, a containing cabinet, a 51-11- ralityof resilient annular members carried by a wall of said cabinet, each oneof said members being engaged by the periphery of one of saiddiaphragms, openings in said wall communicating between the outside airand the spaces between the diaphragms.

5. Ina loud speaker a driving element, a plurality of conical diaphragmsof different angularities operatively connected to said driving element,a containing cabinet, 8. wall of said cabinet in proximity to theperipheries of said diaphragms and means for adelement, a containingcabinet, a wall justing the proximity of said peripheriesto said wall.

6. In a loud speaker a driving element, a plurality of cone diaphragmsof different angularities operatively connected with said drivingelement, a containing cabinet, a plurality of resilient annular memberscarried by a wall of said cabinet, each one of said members bein engagedby the periphery of one of said (Iiaphragms, openings in said wallcommunicating between the outside air and the spaces between thediaphragms, and means for adjustin the pressure of engagement of saiddiapbragms on said resilient members.

7. In a loud speaker a driving element, a plurality of cone diaphragmsof different angularities operatively connected with said drivingelement, a containing cabinet having openings'therein, a plurality ofsupporting members, one disposed between the peri hery of each diaphragmand the wall of sai cabinet, certain of said openings being situated insaid walls between said members.

8. In a loud speaker a driving element, a plurality of coaxial conicaldiaphragms of different angularities connected together, a containingcabinet, resilient annular pads on a wall of said cabinet, the peripheryof one of the diaphragms engaging each of said pads and means forregulating the pressure of this engagement.

9. In a loud speaker a driving element, a plurality of cone dia hragmsof different angularities operative y connected to said driving element,a containing cabinet, a wall of said cabinet engaging the eri heries ofsaid diaphragms a second wa l 0 said cabinet carrying said drivingelement and means for adjusting the pressure of the diaphragms on thefirst said wall.

10. In a loud speaker a driving element, a plurality of coaxialdiaphragms of different angularities operatively connected to saiddriving element, an unenclosed space between the peripheries of saiddiaphragms and means for variably adjusting the pressures on thediaphragms.

KENNETH SEBASTIAN SAMUEL SPENCER.

